This invention relates generally to couplers for railway cars, and more particularly to a height adjuster for the coupler that is carried out with the use of a shim disposed between the coupler carrier and the carrier wear plate.
Problems in maintaining the required coupler heights have persisted over the years for the railroad industry for both new and existing railway cars. Measured from the top of the rail to the center of the face of the coupler knuckle, the American Association of Railroads (AAR) requires a minimum of 321/2 inches and a maximum of 341/2 inches for empty cars and a minimum of 311/2 inches and a maximum of 331/2 inches for loaded cars. Various approaches have been taken in attempts to comply with these standards, among these being the use of a shim secured over the coupler carrier wear plate. The coupler knuckle or face is therefore elevated a distance equal to approximately three times the thickness of the shim because of the length of the coupler draft bar. However, these coupler carrier shims are required by the AAR to be of a minimum 1/4 inch thickness because of the wear to which they are subjected upon cross shifting movement of the coupler draft bar. A 3/4 inch vertically upward adjustment is therefore the minimum made possible with the use of such shims.
On the other hand, shims of less than the 1/4 inch minimum thickness could be inserted between the coupler carrier and the wear plate to provide for finer adjustments at the coupler knuckle. An approach taken in the past for gaining access to the shim was to remove the coupler, which is a tedious and time-consuming task, so as to provide the necessary vertical clearance to raise the wear plate above its carrier member. Also, the shim could be placed there before the coupler is installed new, but it would be a speculative approach since coupler height can vary from car to car.
In order to provide easier access for the shim between the coupler carrier and the wear plate, striking castings have heretofore been provided with front and/or side openings through which the shim may be extended after elevating the wear plate. However, these openings are typically plain openings which serve to only weaken the striking casting at that location thereby causing premature failure due to torsional, bending, fatigue and other stresses to which the casting is subjected. Such shims are, moreover, of substantially rectangular shape and therefore provide inadequate support for the coupler carrier wear plate which normally has a large center section extending toward the draft bar yoke.